(A) Field of the Invention
This invention relates to a method of and apparatus for measuring the air leakage rate of a structure, e.g. a building or a part thereof, for the purpose of assessing the efficiency of the structure in resisting energy loss.
(B) Description of the Prior Art
The ability of building structures to assist energy loss is nowadays of significant importance because of the very high cost of energy used for heating and cooling buildings. Much attention has been paid to increasing the insulation factors of walls and ceilings, but energy gains achieved by this means are minimized if the building has poor air tightness, as energy can escape around the insulation. It is therefore necessary to reduce air leaks by providing proper caulking, weather stripping, etc.
Until now, no convenient way has existed of measuring the air tightness of buildings with any degree of accuracy. Measurements have been made of test houses, for example, but the conventional equipment employed is extremely bulky, difficult to use and requires structural modification to the house. Further, measurements made for a test house cannot reliably be employed for other houses because individual houses, even if made from the same plans, may differ considerably in air tightness according to the degree of care taken by the builders in ensuring that joints and seals are formed properly.
There is therefore a need for convenient apparatus for measuring the air tightness of a structure which is sufficiently portable and adjustable that it can conveniently be used for most existing buildings without requiring significant structural modifications. Such equipment should enable the air tightness of the structure to be tested so that additional caulking, weather stripping and the like could be installed if required.